Electronic device for safety footwear

ABSTRACT

A protective sole of an item of footwear for electric and electrostatic charges comprises a sole unit comprising at least a midsole portion and an outsole portion. The midsole portion is connected on top of the outsole, with the midsole portion oriented toward the wearer while the outsole portion is against the ground when the item of footwear is worn. An electronic device is inserted in the sole unit, and comprises circuitry with a first contact end exposed on a top surface of the midsole portion to be electrically connected with the wearer, and a second contact end to be electrically connected with the ground via the outsole portion. A substrate supports the circuitry and is adapted to be mounted in the sole unit. Electronic components are between the first and the second contact ends, on the circuitry, and concurrently performing a ground of electrostatic charges and insulation against electric discharges. A body made of an electrically insulated molding compound or conformal coating is accommodated in the sole unit, the body being sized to completely cover the at least one electronic component.

FIELD OF THE APPLICATION

The present application relates to safety footwear and, more particularly, to footwear equipped with an electronic device for electro-hazard and/or electro-static protection.

BACKGROUND OF THE ART

Work shoes incorporating resistors or electronic circuits have been disclosed to offer a way to dissipate static charges from the human body. Work shoes provide very difficult conditions to electronic devices incorporated within them. Work shoes are submitted to continuous flexions, walking impact and shocks, changing weight compressions, hydrolysis, varying temperatures, etc. Long term reliability of the electronic devices integrated in these shoes is essential since these shoes are worn on jobsites where static dissipative performance and electro-hazard protection are crucial.

Protective footwear certification organizations (for example, the Canadian Standard Association) are concerned about static-dissipative work footwear that use electronic components like resistors. Certain organizations require flexion and compression tests of specimens to make sure they can live up to real-world conditions. Prior art shoes often fail to provide a stable and constant level of static-dissipative performance or electro-hazard protection under such conditions.

The hydrolysis problem (i.e.: humidity penetrating into the sole of a shoe) has a particularly negative effect on the permanent functioning of electronic components. Work footwear constructed according to the prior art fail to supply a consistent static-dissipative performance and electro-hazard protection when affected by hydrolysis. The same can be said with regards to varying temperatures.

More importantly, the protection of wearers against the risk of electrocution in conventional industrial settings requires particular attention to the integration of electronic components and electronic devices into footwear. For example, in North America, industrial manufacturers frequently use 600 volts alternative current power (600V A.C., 50-60 hertz) and thus, work footwear must be able to protect wearers against the grounding of such power. Electronic components have shown to be fragile when submitted to alternative current. High voltage is destructive to the components and impairs their proper functioning. Research (lab tests and real-world tests) points out that the use of carbon-powder enriched elastomers (plastics, rubbers or the like) near electronic components increases the risk of destruction of such electronic components. A 600 Volts A.C. “phase-to-neutral” electrical tension applied for 10 seconds to work footwear constructed according to the prior art destroys the electronic devices: the conductive elastomer is carbonized and the shoes set on fire.

Furthermore, it is a difficult task for shoe manufacturers to integrate small electronic devices into footwear. The connection between the electronic device and the wearer interface (i.e.: insole) or the ground interface (i.e.: outsole) requires particular attention. Prior art shoe design has not entirely taken into consideration the particularities of the shoe industry in the integration of electronic components: shoe manufacturers require an easier way to integrate electronic devices into their goods.

SUMMARY OF THE APPLICATION

It is therefore an aim of the present disclosure to provide a novel electronic device that addresses issues associated with the prior art.

It is a further aim of the present disclosure to provide a novel method for assembling electronic devices into footwear items that addresses issues associated with the prior art.

Therefore, in accordance with the present application, there is provided an electronic device to be inserted in the sole of a footwear item, comprising: circuitry with at least a first contact end to be electrically connected with the wearer and a second contact end to be electrically connected with the ground; a substrate supporting at least part of the circuitry and adapted to be mounted to the sole; at least one electronic component between the first and the second contact ends, on circuitry, the at least one electronic component concurrently performing a ground of electrostatic charges and insulation against electric discharges; a body made of an electrically insulated molding compound or of conformal coating, the body being sized to completely cover the at least one electronic component.

Further in accordance with the present application, there is provided a protective sole of an item of footwear for electric and electrostatic charges, the protective sole comprising: a sole unit comprising at least a midsole portion and an outsole portion, the midsole portion connected on top of the outsole, with the midsole portion oriented toward the wearer while the outsole portion is against the ground when the item of footwear is worn; and an electronic device to be inserted in the sole unit, and comprising: circuitry with at least a first contact end exposed on a top surface of the midsole portion to be electrically connected with the wearer, and a second contact end to be electrically connected with the ground via the outsole portion; a substrate supporting at least part of the circuitry and adapted to be mounted in the sole unit; at least one electronic component between the first and the second contact ends, on the circuitry, the at least one electronic component concurrently performing a ground of electrostatic charges and insulation against electric discharges; and a body made of an electrically insulated molding compound or of conformal coating accommodated in the sole unit, the body being sized to completely cover the at least one electronic component.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of an electronic device constructed in accordance with a first embodiment of the present disclosure;

FIG. 2 is a bottom perspective view of the electronic device of FIG. 1;

FIG. 3 is a top view of the electronic device of FIG. 1;

FIG. 4 is a bottom view of the electronic device of FIG. 1;

FIG. 5 is a side view of the electronic device of FIG. 1;

FIG. 6 is a cross-sectional view A-A of FIG. 5;

FIG. 7 is a top assembly view of the electronic device of FIG. 1;

FIG. 8 is a bottom assembly view of the electronic device of FIG. 1;

FIG. 9 is a top perspective view of a footwear sole incorporating the electronic device of FIG. 1;

FIG. 10 is a top assembly view of the footwear sole of FIG. 9;

FIG. 11 is a bottom assembly view of the footwear sole of FIG. 9;

FIG. 12 is a top perspective view of an electronic device constructed in accordance with a second embodiment of the present disclosure;

FIG. 13 is a top view of the electronic device of FIG. 12;

FIG. 14 is a perspective view of a an electronic device constructed in accordance with a third embodiment of the present disclosure;

FIG. 15 is a top view of the electronic device of FIG. 14;

FIG. 16 is a top assembly view of the electronic device of FIG. 14;

FIG. 17 is a bottom assembly view of the electronic device of FIG. 14;

FIG. 18 is a schematic view of a top of a printed circuit of the electronic device of FIGS. 1, 11 and 13;

FIG. 19 is a schematic view of the bottom of the printed circuit of the electronic device of FIGS. 1, 11 and 13;

FIG. 20 is a top plan view of an electronic device constructed in accordance with a fourth embodiment of the present disclosure;

FIG. 21 is a top plan view of the electronic device of FIG. 20, with an insulated molding body removed from a printed circuit;

FIG. 22 is a bottom plan view of the electronic device of FIG. 21;

FIG. 23 is a top perspective view of a footwear sole incorporating the electronic device FIG. 20; and

FIG. 24 is an assembly view of a footwear midsole and outsole incorporating the electronic device of FIG. 20.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Description of the First Embodiment of the Electronic Device

Referring to FIGS. 1 to 8, an electronic device in accordance with a first embodiment is generally shown at 1. The electronic device 1 is used as part of a shoe to dissipate electric charges and to protect the wearer of the shoe from electro hazards, and therefore defines a conductive path via a circuitry. The electronic device 1 has a top interface 2 exposed in its top surface. A body 3 of the electronic device 1 is shaped as a disc, or in any other suitable shape. The body 3 is made of an insulated molding material, such as thermoplastic hot melt, of a conformal coating, or of any other appropriate polymeric material or the like providing protection from moisture. The conformal coating may be acrylic, epoxy, polurethane, silicone, poly-para-xylylene (parylene) or amorphous fluoropolymer, among other possibilities.

The body 3 encapsulates electronic components that perform the electrostatic and/or electrical protective functions. More specifically, a printed circuit 4 (such as a printed circuit board or other type of circuitry 4) is inside the body 3, and is connected to the top interface 2 and a bottom contact plate 5. The bottom contact plate 5 may or may not be an integral part of the printed circuit 4. The bottom contact plate 5 is exposed through a bottom hole 6 in the body 3.

Referring to FIGS. 6 to 8, an interior and an assembly of the electronic device 1 are illustrated. The top interface 2 is part of a substrate comprising a top conductive insert 7 that is in contact with the printed circuit 4, through a rectangular prism 9. The insert 7 is for instance made of a conductive elastomer, amongst other possibilities of substrate materials. The prism 9 may have various shapes, as long as it contacts the printed circuit 4. The printed circuit 4 has electronic components 8 mounted thereto, such as resistors, transistors or the like.

In order to be connected with the conductive insert 9, the printed circuit 4 is part of the conductive circuitry, which may also comprise a top contact plate 10 (FIG. 7), being in contact with the prism 9. Accordingly, the printed circuit 4 is in contact with both the insert 7, and the bottom contact plate 5.

In the embodiment of FIGS. 1 to 8, the body 3 may be overmolded onto the other components of the electronic device 1, leaving at least the top interface 2 and the bottom contact plate 5 exposed. The hole 6 in the body 3 allows the electronic device 1 to be used in conjunction with cemented and direct-attach sole assembly processes.

Referring to FIG. 9 to 11, the electronic device 1 is shown being inserted in a sole 11 of a shoe. The sole 11 has a midsole 12 that may be electrically insulated (to some extent), and features a hole 14, for instance in the heel, to accommodate the electronic device 1. The hole 14 is sized and shaped for snugly receiving the electronic device 1. An outsole 13 is at a bottom of the midsole 12, and is partly electrically insulated.

Referring to FIG. 10, an interface is provided on a top surface of the outsole 13, for contact with the electronic device 1. In the illustrated embodiment, the interface has a large cylinder 15, upon which is concentrically positioned a small cylinder 16, projecting upwardly from the large cylinder 15. Accordingly, the small cylinder 16 is mated into the bottom hole 6 of the electronic device 1, and an annular bottom of the body 3 sits on the large cylinder 15. The small cylinder 15 is made of a conductive material, and contacts conductive zones 17 on a bottom of the outsole 13. The conductive zones 17 define a conductive path 18 in a bottom of the outsole 13. The conductive path 18 may form only a part of the undersurface of the outsole 13, with non-conductive zones 19 being made of a material with non-marking properties. The non-conductive zones 19 may be made of a material of lesser cost.

Description of the Second Embodiment of the Electronic Device

Referring to FIGS. 12 and 13, an electronic device in accordance with a second embodiment is shown at 20, and does not have a conductive elastomer material. The body 21 is made of an insulated molding material, such as a thermoplastic overmelt encapsulating the electronic components of the circuitry (not shown). A hole 22 is defined in the material of the body 21, and is illustrated having a rectangular section, amongst other possibilities. Accordingly, a top contact plate of the circuitry is exposed through the hole 22. The electronic components are in zone 24, and are encapsulated in the material of the body 21.

The electronic device 20 as shown in the second embodiment presents a cost effective because of the absence of a conductive elastomer insert. However, it may be more difficult to integrate into footwear items, as the manufacturer must make sure the top contact plate 23 of the circuitry is in a permanent and reliable electric contact with the wearer. Consequently, a conductive filler may be used or may be required. The hole in the bottom (similar to hole 6 in FIG. 6) allows the electronic device 20 to be used in conjunction with cemented and with direct-attach sole assembly processes.

Description of the Third Embodiment of the Electronic Device

Referring to FIGS. 14 to 17, an electronic device in accordance with a third embodiment is generally shown at 25, and has two conductive elastomer inserts, namely top conductive elastomer insert 28 and bottom conductive elastomer insert 30. The body 26 is made of an insulated molding material, such as a thermoplastic hotmelt overmolding printed circuitry 29. The conductive elastomer insert 28 has a top interface 27, having a hexagonal shape, or any suitable shape, projecting from a bottom disc portion. Accordingly, the insert 28 is encapsulated in the body 26, with the hexagonal top interface 27 being exposed for contact with a wearer.

The printed circuitry 29 has a top contact plate 31 that is in contact with a rectangular projection 34 (FIG. 17) of the top conductive elastomer insert 28, and a bottom contact plate 33 in contact with the bottom conductive elastomer insert 30. The insert 30 has a bottom interface 32 that is in contact with a conductive zone of the outsole, in similar fashion to the electronic device 1 (FIGS. 1 to 11).

The third embodiment is more expensive to produce than the other two embodiments, as the overmolding process is more complex. However, it provides a simple solution to integrate into cemented footwear items.

Description of the Fourth Embodiment of the Electronic Device

Referring to FIGS. 20 to 22, there is illustrated an electronic device 42 in accordance with yet another embodiment of the present disclosure. The electronic device 42 has a substrate made from an elongated strip of a flexible material (or part flexible material, part rigid material). In an embodiment, the flexible material is a polymer, such as polyimide, polyester, PET, PEEK, or the like. In another embodiment, the flexible material forms flexible electronics with the circuitry thereon. In such a case, the circuitry may be installed on the flexible material in any appropriate way (e.g., screen printing, photolithographic technology, or the like). The elongated strip has a first flexible substrate portion 43 and a second flexible portion substrate 44. The flexible substrate portions 43 and 44 are interconnected by an electronic component housed in body 45. The body 45 is similar to the afore-mentioned bodies and is typically made of an insulated molding compound, a conformal coating or a material that will house electronic components and therefore protect same from temperature, humidity, compression, impacts, etc. The flexible substrates 43 and 44 have conductive elements thereon that will be in contact with the circuitry within the body 45.

More specifically, a first contact plate is generally illustrated at 46 and is on the first flexible substrate 43. The first contact plate 46 is in contact with the foot of the wear or with a conductive sock liner that is in contact with the foot of the wearer. In the illustrated embodiment, the first contact plate 46 is in conductive relation with a conductive portion 47 a on another side of the flexible substrate 43. The conductive portion 47 a is separated from a second contact plate 47 b that is positioned on a bottom surface of the second flexible substrate 44. The second contact plate 47 b is therefore in conductive relation with parts of the outsole as will be shown hereinafter.

Printed circuit 48 may either be flexible or rigid and is housed in the body 45. The printed circuit 48 performs the electrostatic and electric protective functions. In the embodiment of FIGS. 20 to 24, the printed circuit 48 has a sequence of a small-signal transistor 49 (depletion mode, SIPMOS#1), a first resistor 50, another small-signal transistor 51 (depletion mode, SIPMOS#2), a third small-signal transistor 52 (depletion mode, SIPMOS#3), a second resistor 53, and finally another small-signal transistor 54 (depletion mode, SIPMOS#4). It is pointed out that the printed circuit 48 may have more than two resistors. Similarly, more than four depletion mode small-signal transistors may be used. The transistors are the gate threshold of the printed circuit 48, ensuring that the voltage at the resistors is controlled. The resistor opposes a resistance to the voltage, so as to control the current passing through the printed circuit 48.

Referring to FIGS. 23 and 24, there is illustrated the electronic device 42 as positioned in a sole 55 of a footwear item. The sole 55 has a midsole 56 that is relatively insulated (e.g., an electrical resistance being over 35,000,000 ohms according to test method ASTM F2413-05 is well suited for the midsole 56). The outsole 57 is at a bottom of the midsole 56 and is relatively conductive or has parts that are relatively conductive (e.g., an electrical resistance being below 500,000 ohms according to test method ASTM F2413-05 is well suited for the outsole 57). A slot 58 is defined in the midsole 56 and allows a portion of the first flexible substrate portion 43 to pass therethrough so as to have a major portion of the electronic device 42 on a bottom side of the midsole 56, and therefore in contact with the outsole 57. As shown in FIG. 24, there may be defined a cavity in the midsole 56 so as to accommodate the body 45 of the electronic device 42. Considering that the substrate portions 43 and 44 are flexible, they have a tendency to remain in contact with the foot of the wearer, thereby insuring that there remains a conductive path between the foot of the wearer and the electronic device 42.

Description of an Embodiment of the Printed Circuit

Referring to FIGS. 18 and 19, an example of suitable printed circuit is shown at 35 in the form of a printed circuit board, and has a top contact plate 36, small signal transistor 37, resistor 38, small signal transistor 39. A hole 40 in the printed circuit 35 allows electrical contact between the circuit and a bottom contact plate 41.

The small signal transistors 37 and 39 may operate in a depletion mode, and may be SIPMOS, by Infineon #BSS126, among other possibilities. The resistor 38 may be a SEI # RMCF 1/16 6K04 1% TR, among other possibilities.

The electronic devices described herein improve the functioning and long-term reliability of safety footwear by protecting printed circuits and electronic components. The thermoplastic hotmelt molding material offers thermal stability and physical protection against impact shocks, weight compressions and flexions. It also offers a high level of electrical insulation, resisting in some cases a tension of 18,000 Volts with a 1 mm thickness.

Moreover, the electronic devices described herein reduce problems due to hydrolysis by sealing the printed circuits and electronic components. The injection process of the thermoplastic hotmelt molding material assures that components stay dry and protected from humidity.

The electronic devices described herein also provide a solution to reduce the risk of destruction of electronic components in situation of high voltage alternative current discharge. The thermoplastic hotmelt molding material electrically insulates all parts of the disclosed electronic device, significantly reducing the risk of electrical “short” or “arc” from one conductive part to an other (for example: from the top conductive elastomer insert 7 to the small cylinder 16 of the sole, as in FIG. 10). High voltage alternative current may be highly hazardous to human. Consequently, footwear incorporating electrical devices must be designed to assure enhanced safety.

The electronic devices described herein provides a reliable solution to comply with standards on protective footwear incorporating electronic components like resistors, and simplifies the integration of electrical devices into footwear by shoe manufacturers. The shape of the disclosed electronic device makes it easier for manufacturers of footwear to assure a good electrical contact from the top layers (insole, construction board) of the shoe to the top contact plate (10) of the electronic device and from the bottom contact plate (5) to the conductive zones (17) of the outsole.

The novel method of assembly simplifies the integration of electrical devices into footwear by shoe manufacturers. The method ensures a reliable electrical connection between the top layers (insole, construction board) of the shoe and the top interface 2 of the electronic device. The method also ensures a reliable electrical connection between the bottom contact plate 5 of the electronic device and the conductive zones 17 of the outsole, and provides an efficient dissipative performance without sacrificing the “non-marking” and other important physical properties of the outsole. 

1. An electronic device to be inserted in the sole of a footwear item, comprising: circuitry with at least a first contact end to be electrically connected with the wearer and a second contact end to be electrically connected with the ground; a substrate supporting at least part of the circuitry and adapted to be mounted to the sole; at least one electronic component between the first and the second contact ends, on circuitry, the at least one electronic component concurrently performing a ground of electrostatic charges and insulation against electric discharges; a body made of an electrically insulated molding compound or conformal coating, the body being sized to completely cover the at least one electronic component.
 2. The electronic device according to claim 1, wherein the substrate is made of a flexible strip of elongated material.
 3. The electronic device according to claim 2, wherein the circuitry defines a conductive path passing from one side of the flexible strip to the other side of the flexible strip.
 4. The electronic device according to claim 1, wherein the electrically insulated molding compound is a thermoplastic hotmelt based on polyamide.
 5. The electronic device according to claim 1, wherein the at least one electronic component is a resistor.
 6. The electronic device according to claim 1, wherein the at least one electronic component is at least one set of two depletion mode small-signal transistors and a resistor.
 7. The electronic device according to claim 1, wherein the substrate is at least one electrically conductive insert connected to at least one of the first and the second contact ends of the circuitry.
 8. The electronic device according to claim 7, wherein the electrically conductive insert is made of at least one of thermoplastic polyolefin elastomer and conductive rubber.
 9. The electronic device according to claim 1, wherein the conformal coating is made of at least one of acrylic, epoxy, polurethane, silicone, poly-para-xylylene (parylene) and amorphous fluoropolymer.
 10. The electronic device according to claim 1, wherein the body covers at most partially the first and second contact ends of the circuitry.
 11. The electronic device according to claim 1, wherein the circuitry comprises a printed circuit board, and the at least one electronic device is on the printed circuit board.
 12. A protective sole of an item of footwear for electric and electrostatic charges, the protective sole comprising: a sole unit comprising at least a midsole portion and an outsole portion, the midsole portion connected on top of the outsole, with the midsole portion oriented toward the wearer while the outsole portion is against the ground when the item of footwear is worn; and an electronic device to be inserted in the sole unit, and comprising: circuitry with at least a first contact end exposed on a top surface of the midsole portion to be electrically connected with the wearer, and a second contact end to be electrically connected with the ground via the outsole portion; a substrate supporting at least part of the circuitry and adapted to be mounted in the sole unit; at least one electronic component between the first and the second contact ends, on the circuitry, the at least one electronic component concurrently performing a ground of electrostatic charges and insulation against electric discharges; and a body made of an electrically insulated molding compound or conformal coating accommodated in the sole unit, the body being sized to completely cover the at least one electronic component.
 13. The protective sole according to claim 12, wherein the substrate is made of a flexible strip of elongated material, with the circuitry defining a conductive path passing from one side of the flexible strip to the other side of the flexible strip, with the contact ends being on opposite sides of the flexible strip.
 14. The protective sole according to claim 12, wherein the electrically insulated molding compound of the body is a thermoplastic hotmelt based on polyamide.
 15. The protective sole according to claim 12, wherein the at least one electronic component is at least one set of two depletion mode small-signal transistors and a resistor.
 16. The protective sole according to claim 12, wherein the substrate is at least one electrically conductive insert connected to at least one of the first and the second contact ends of the circuitry.
 17. The protective sole according to claim 16, wherein the electrically conductive insert is made of one of a thermoplastic polyolefin elastomer and of a conductive rubber.
 18. The protective sole according to claim 12, wherein the circuitry comprises a printed circuit board, and the at least one electronic device is on the printed circuit board.
 19. The protective sole according to claim 12, wherein the body is positioned in a cavity of the midsole portion, and the second contact end is in contact with conductive means in the outsole portion.
 20. The protective sole according to claim 12, wherein the midsole portion is made of a relatively insulating material, and the outsole is made of a relatively conductive material.
 21. The protective sole according to claim 12, wherein the conformal coating is made of at least one of acrylic, epoxy, polurethane, silicone, poly-para-xylylene (parylene) and amorphous fluoropolymer 